JAKARTA, Indonesia - A moderate earthquake struck early Monday off the coast of Indonesia's Sumatra island, killing four people, officials and witnesses said.

The 5.8-magnitude tremor was centered about 45 miles southwest of Banda Aceh, the capital of Aceh province, the US Geological Survey said on its Web site.

Aceh province, on the northern tip of Sumatra island, was the hardest hit by the 2004 Indian Ocean tsunami, with at least 167,000 deaths. No tsunami warning was issued after Monday's quake.

The quake was followed by a 5.5-magnitude aftershock about 30 minutes later, the USGS reported.

At least four people were killed in one village in north Sumatra when two houses collapsed, a witness told local radio station el-Shinta. Scores of other buildings were cracked, he said.

Indonesia, the world's largest archipelago, is prone to seismic upheaval due to its location on the so-called "Ring of Fire," an arc of volcanos and fault lines encircling the Pacific Basin.